janssnet

Eurobricks Vassals
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About janssnet

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    Technics
  • Which LEGO set did you recently purchase or build?
    LEGO Technic Super Car - 8070

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    Netherlands

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  1. The protocol Lego and/or BuWizz is using to steer motors, I do not know. What I do know is that Lego is often used in robotic and educational environments for prototyping. In these situations PWM (Pulse Width Modulation) is widely used as the preferred protocol to control servos and motors (Arduino for instance has standard libraries for this - Servo.h). And that is the market Geekservo is targeting (I assume), offering a Lego-brick compatible servo that understands a standard (50 Hz) PWM signal. Perfect for rapid prototyping. The great thing is that (most) standard RC electronics also support this 50Hz PWM signal. The RC receiver converts a 2.4GHz radio signal into a PWM signal which is understood by (most) ESC's and servos. No need to stay within IR or Bluetooth distance anymore and tons of new possibilities. The wiring of a (Geek-) servo: 1: GND, 2: +5-6V 3: Pulse (this is the PWM signal)
  2. There is indeed a significant difference in precision.The LEGO servo offers 15 positions. The Geekservo in this car has a 'dead band' of 4┬Ás, which means, when using the 'normal' PWM pulse range of 1000ms - 2000ms, there are 250 positions. The ESC has no role in this. The ESC drives the motor, not the servos. Servos are directly connected to the RC Receiver. Why the resolution of the LEGO Servo is limited, I do not know. But I'm sure others have a perfect explanation for this .....
  3. Thanks for your reply. Building these models is not too difficult. 1. Build your LEGO car 2. Mount your (non-LEGO) motors (this is the tricky part, happy to explain in further detail) 3. Put your RC electronics in (ESC's, servos (Geekservos are great), RC receiver, battery) 4. GO!! Clearly it's not as sequential as described. The chassis should have provision for the electronic to make it work and look good, but these are the basics steps. Here is a link to the instruction PDF of the LBOW iWD2: https://drive.google.com/file/d/1lWDDGeADSEPiHKbdlmpJBG0MDvsfXlLK/view?usp=sharing
  4. Finally finished a first version of a LEGO RC Car with 2 in-wheel, brushless motors. While I know some of you hate the combination of RC electronics and LEGO, others enjoy these hybrid models (hence this post). If you are more the purist type and in favour of LEGO only, please skip this. If you like stretching the envelope using (RC) electronics please have look and let me hear your thoughts. While searching for brushless in-wheel motors I ran into the ideal product: Turnigy Multistar 4225-610Kv. It mounts easily onto LEGO (same measurements) and fits almost any 56-rim. The result is spectacular. Great speed, no wear-out, all traction goes to the wheels, no gears necessary. Sadly, it turns out this motor is no longer available (working on an alternative). Car also includes an (adjustable) software differential running on an Arduino Nano, works surprisingly well. When fully applied the car has serious oversteer, when turned to 0 the car has understeer. The body of the car is a 54100 modified boat hull . It took some cutting but ended up nicely. Please have a look at the video here:
  5. Please have a look here Bottom-line: Length x Diameter x Thickness (in mm) Soft spring 25 x 7 x 0.4. (when using without the LEGO spring housing, just the separate spring, you can use any length of course) Stiff spring 25 x 7 x 0.7
  6. Here is the video Does this answer your questions? And is it worth doing a separate post?
  7. Thanks, works! Today or tomorrow I'll do a video to wrap up my findings to make LEGO work with custom motors, including pinion gear, mounting tricks, etc.
  8. This buggy contains a 3600KV brushless motor (2838). It has a pinion made from a LEGO axle and it runs a seriously good working drive-train. Together with the new 42109 differential and a (new?) 2D suspension method it turns out to be a fun car to drive. Please watch a video here. Especially the suspensions are worth having a look. More and more I'm using custom springs to create all sort of applications. Useful and useless. Almost useless is the spring-lock to open the hood. Very useful are the long front springs and the two-dimensional rear springs. Please let me know your comments. No building instructions available yet. If there is a need, let me know.
  9. Thanks for sharing. I'm afraid this is not going to work. The bike will not be able to drive in a straight line. The 45590 is to stiff to allow the front wheel to move freely to keep the bike straight. It's hard to explain, requires serious physics. Bottom-line, if the front wheel has a castor-angle (approx. 30 degrees) and is able to move freely, it will automatically keep the bike straight (at a certain minimum speed). Hope this helps.
  10. Not exactly sure how you did it. Can you share a picture? For the front suspension of the upcoming Bobber-bike, I came up with this idea. Not 100% happy yet, may have to loosen the springs a bit (as Bartybum suggested). Have a look here
  11. Did a quick setup. Took a car gyro (only one axis) mounted it vertically on the bike. Put it on reverse, so when the bike falls over to the left, the steering turns also left, to compensate (counter-steering) and to put the bike straight again. Made a quick video, please find it here. Conclusions: - It works! Although less stable when going straight than without gyro (which might be a matter of adjusting the sensitivity of the gyro), the steering becomes far less unstable. It almost works like 'going back to center' steering. - Springs continue to be necessary for the steering axles. Tried without, but it makes the bike very very sensitive for any change in steering direction by the servo. Almost impossible to steer. Seriously considering to put it on the Bobber-bike, for which every bump in the road currently seems to be too much. What do you think, will the gyro stabilise for bumps in the road? Thanks again for your suggestions. Great stuff!!
  12. Interesting thought! Have a gyro available from an old car project. With the gyro installed the connection to the steering servo would not require springs, can be done with fixed axles. Will be interesting to see if this reacts as quick as a self-stabilising bike to keep it straight. Have never seen it on the real RC motor bikes though ....
  13. Yes, ran into 2 problems. The strength of the springs need to be very accurate to enable the front wheel to move freely, the original LEGO springs are too stiff for this application. Secondly, I couldn't find a way to fit the standard spring in the (very limited) space available. And to be honest, I enjoy these custom springs very much. Lots of useful and useless possibilities. The most useless is a suspended seat on the Bobber-bike, since it's hardtail. Had to consider the convenience of the driver :))
  14. In an attempt to create an RC LEGO motorbike, I had to figure out a steering method. Moving a weight from left to right was (successfully) done before, but I couldn't find LEGO bikes with counter-steering. Inspired by the videos of many real RC bike lovers, I came up with this LEGO-ish implementation. It's not for LEGO purists, it contains modified parts. But it demonstrates pretty nice how counter-steering works and how it can be implemented on a LEGO bike (using a servo). I therefore thought it might be of interest to some of you. If modifying LEGO parts makes you sick, please skip this video. If you enjoy creating new parts (out of other LEGO parts), great! Let me hear your thoughts. On this matter, I personally start to enjoy the use of custom springs more and more (will do a separate video on this subject) and ... I'd love to make a case for an axle with one ball socket. Together with a (custom) spring, can be used in almost any vehicle for suspension or anything else. Have a look at the video and you'll see what I mean. Was an essential element to create this steering. Enjoy watching, looking forward to hear your comments. https://youtu.be/AZQkJCd0VKg
  15. That's great, thanks for sharing. That could indeed be the reason for this notch. Thanks.